The present invention is directed to a method, printing medium, coating, composition and activator for authenticating a product or a document to detect fraudulent duplication and counterfeiting.
In today's business environment, most documents, such as coupons, tickets, labels, checks, etc., and product packaging demand a simple verification process with a tamper evident security feature to prevent the fraudulent duplication and counterfeiting thereof.
The check market alone has encountered an estimated eleven billion dollar loss per year as a result of fraud.
The advent of color copiers and the improvements achieved in the visual quality of copies produced by such photocopiers has contributed to the fraudulent duplication and counterfeiting of valuable documents.
In U.S. No. Pat. 5,354,723, a method for protecting against duplication with a color copier is disclosed wherein a contrast color is printed on a background color. The contrast color is printed with a printing medium which also allows activation by a rubbing action.
The printing medium in U.S. Pat. No. 5,354,723 includes a color former leuco dye and activating phenolic resin which are printed and when mechanical pressure or rubbing is applied, the frictional heat causes a color change. This permits the verification that the document is an original. Applicant hereby incorporates by reference the disclosure of U.S. Pat. No. 5,354,723.
One disadvantage of the use of the leuco dye and activating phenolic resin is that temperatures above 45.degree. C. can cause a premature color development. Temperatures above 45.degree. C. are typical when a sheet of paper, having the leuco dye and activating phenolic resin applied with a printing medium, is passed through a photocopier, indirect or direct thermal printers, or a laser printer which is used to print the label, ticket, check or other information for which the document is to be used.